Baffle packing for heat exchangers



H. W. HOW

BAFFLE PACKING FOR HEAT EXCHANGERS Filed Sept. 4, 1930 Sept. 8, 1931.

HABLAN W. HOW, OF WARREN,

Patented Sept. 8, 1931 UNITED STATES PATENT OFFICE PENNSYLVANIA,ASSIGNOR T0 STRUTHERS-WELLS TITUSVILLE CORPORATION, OF WARREN,PENNSYLVANIA, A CORPORATION OF MARYLAND BAFFLE PACKING FOR HEATEXCHANGEBS Application led September 4, 1930. Serial No. 479,659.

This invention relates to a packing for the baffles of heat exchangers.In heat exchangers the bafiies which divert the Huid in circulation sothat it will pursue a longer course should fit` closely to the wall ofthe enclosing shell in order to avoid leaks which permit a short-cut inthe movement of the fluid and reduce the efficiency of the exchanger.

It is therefore the objectof this invention to provide a packing betweenthe baffle and the wall of the shell which permits the baffle and thetubes associated therewith to be readily and conveniently introducedinto the shell and removed therefrom and still insure a tight jointbetween the baffle and the shell when the apparatus is in use so as toobtain the maximum efficiency.

In the accompanying drawings:

Figure 1 is a vertical longitudinal section of a heat exchanger equippedwith this invention.

Figure 2 is a horizontal section of the same taken on line 22 Fig. 3.

Figure 3 is a cross section taken on line 3 3 Fig. 1.

Figure 4 is a fragmenetary cross section, on an enlarged scale, taken online 4-4 Fig. 5, and showing the packing between a longitudinal edge ofthe baffle and the adjacent part of the shell.

Figure 5 is a horizontal section taken on line 5'-5 Fig. 4.

Figures 6 and 7 are fragmentary longitudinal sections of the baffle andthe packing strip thereon showing different ways of arranging theopposing ends of adjacent sections of the packing strip.

In the following description similar characters of reference indicatelike parts in the several figures of the drawings.

The numeral 10 represents the shell, casing or housing of the heatexchanger which is preferably made of sheet metal and arrangedhorizontally and provided with an inlet 1l for one of the fluids to becirculated and an outlet 12 whereby this fluid may discharge from theshell, said inlet and outlet being preferably constructed in the form oftubular necks which are arranged diamctrically opposite each other onthe upper and lower sides of to the front end thereof.

At its front end the shell is provided with an annular attaching ring orcollar 13 the face of which is provided with an annular recess or rabbet14 which contains a gasket or packing 15. At the rear end of the shellthe same is provided with an annular attaching ring or collar 16 whichforms part of a stuffing box as will be hereinafter described and whichcontainsan internal annular rabbet or enlarged bore 17.

Within the shell a plurality of sets of heat exchanger tubes is arrangedlengthwise, two sets 18 and 19 being shown in the present instance, theupper set 18 being arranged above the center of the shell and the lowerset 19 below this center.

The front ends of these tubes are secured to a front tube sheet 20 whichbears with the rear side of its marginal part against the gasket 15.Arranged in front of the shell and the front tube sheet is a hollowmanifold body 21 which is provided at its rear end with an annularrabbet or recess 22 containing a gasket or packing 23 bearing againstthe front side of the marginal part of the front tube sheet 20, thelatter being clamped between the front attaching ring 13 and the rearend of the manifold body 21 by means of fastening bolts 24 connectingthe adjacent parts of the attaching collar 13 and this manifold body, asshown in Figs. 1 and 2.

On its upper side the manifold body is provided with an inlet 25 foranother of the fiuids to be circulated and on its lower side with anoutlet 26 for this fluid, said inlet and outlet preferably having theform of tubular necks. Extending horizontally across the central part ofthe front manifold body is a partition 27 which divides the interior ofthe front manifold body into an upper connecting chamber 28 whichcommunicates with the front ends of the up sets of tubes 18, and a lowerconnectln chamber 29 which communicates with the front ends of the lowerset of tubes 19, said partition 27 having its rear edge fitted againstthe adjacent central -par't of the the shell adjacent front tube sheet2O through the medium of a packing or gasket 39 so as to form aleaktight joint therebetween.

Arranged in front of the front manifold body is a cover 31 which isprovided with a central horizontal rib 32 engaging with the front edgeof the partition 27 through the medium of a gasket or packing 33 andhaving its marginal part connected with the rear end of the manifoldbody by means of bolts 34 and also bearing against a gasket or packing35 which is seated in an annular recess or rabbet 36 on the front end ofthe manifold body, as best shown in Fig. 1.

The rear ends of the several heat exchanging tubes are secured to therear tube sheet 37 which latter is provided at its edge with a forwardlyprojecting joint sleeve 38 which extends forwardly into the interior ofthe shell 10. Arranged in rear of the rear tube sheet is a manifoldcover 39 forming a connecting chamber 40 which places the rear ends ofthe upper and lower sets of heat exchange tubesin communication witheach other. Adjacent to its margin this rear cover is provided with aforwardly projecting annular flange 41 which projects into the rabbet orrecess 17 of the rear attaching collar and bears against a packing 42therein. The marginal parts of the rear cover 89 and the rear attachingring 16 are connected with each other bv means of bolts 43 so that upontightening these bolts the packing 42 will be compressed and heldtightly around the sleeve 38 so as to prevent leakage from the spacewithin the shell to the rear ends of the heat exchange tubes while atthe same time permitting the rear tube sheet 37 to move lengthwise ofthe shell in response to expansion and contraction of the heal exchangetubes resulting from changes in temperature of the fluids which arecirculated through the shell and the heating tubes.

Arranged lengthwise between the upper and lower sets of the heat tubes1S, 19 is a baille 44 which preferably has the form of a flat plate madeof metal and extending in a horizontal plane. This baffle is connectedat its front end with the rear side of the front tube sheet 20 by meansof a welded joint 48 or other suitable means while the rear end of thisbaille terminates short of the rear tube sheet 39 so as to form atransfer gap or passage 49 therebetween. The longitudinal edges of closeto the inner longitudinal side of the wall of the shell so that thecirculating fluid entering, say through the inlet 11, will be compelledto be passed-horizontally rearward through the upper passage 50 formedbetween the baflle 44 and the upper part of the shelll` thencedownwardly through the` passage 49, thence horizontalh7 forward throughthe lower passage 51 formed bethis baille are arranged' 'U-shape form intween the baffle 44 and the lower part of the shell and thence outthrough the lower outlet 12. The other fluid which is to be circulatedmay enter, for example, through the inlet 25, thence through the upperconnecting chamber 28, thence rearwardly through the upper set of tubes18, thence downwardly through the rear connecting chamber 40, thenceforwardly through the lower set of tubes 19, thence downwardly throughthe lower connecting chamber 29 and out through the outlet 26.

In the use of this apparatus the relatively hot and cold liquids to becirculated may be passed respectively either through the interior of thetubes or through the shell along the exterior of the tubes and thesefluids may either move through their respective passages in parallelismor the same may move in opposite directions through their respectivepassages, the particular manner o handling these fluids being governedby conditions where the apparatus is installed, also the character ofthe fluids between which the heat is to be interchanged. In all caseshowever, the temperature of the fluid on the exterior of the tubes andthe temperature of the fluids on the interior of these tubes influenceone another by an exchange of the heat, tending to raise the temperatureof the cooler liquid and lowering the k,temperature of the hot liquid.

In order to obtain the maximum heat eX- changing efliciency of thisapparatus it is necessary to maintain a leaktight joint between thelongitudinal edges of the baille 44 and the wall 10 of the shell so asto prevent the fluid entering the shell from passing through the jointsbetween the longitudinal edges of the baffle 44 and the wall 10 and makea short-cut from the inlet to the outlet end of the shell instead ofbeing compelled to travel to and fro through out the length of the shelland around the rear edge of the baille which constitutes a very muchlonger course for the fluid and insures a greater transmission of theheat from one of the streams of fluid to the other.

To insure a practically tight joint between the longitudinal edges ofthe baflle and the wall of the shell for this purpose, packing means areprovided which are preferably constructed as follows:

Between each longitudinal edge of the baffle and the adjacent part ofthe shell is arranged a packing strip which in its preferred form ismade up of a plurality of longitudinal sections which have theiropposing ends arranged adjacent to each other' so that in effect theyproduce one continuous strip. Each of these sections is preferablyconstructed of sheet metal which is of cross section and provides atransverse bearing web 52 which engages with its outer side against theinner side o the .adjacent pa't of the shell wall 10, as

best shown in Figs. 4and 5,and two longitudin al' legs vo rillan'ges 53proj ecting' inward'- ly,i'1 'om1the'opposite longitudinal edges of theweb and .engaging with opposite ilat sides of the adjacent longitudinaledge portion of the -baille 44, as. shown in the same figures.l

The several sections of cach packingstrip areyieldinglyheldin'engagelnent with the Shell wall by spring means which in itspre,- ferred construction consists of an undulatcd orA serpentine shapedstrip of spring meLal 54 vwhich `is arrangedlbetween the inner side ofvthe` packing strip webs 52 and the adjacent longitudinal edge of thebaille 44, and bears with its alternating crests against the adjacentweb of the'paking strip and the. longitudinal edge of the baille, asbest show-n in Fig. 5. By this means the stripfo spring metal 54 tendsto constantly press thepacking strip away from' the baille -and intoen-l gagement with the shell wall and hereby maintain a ipracticallytight joint between the opposing longitudinal surfaces of the samethrough which the respective circulating fluid cannot pass-and take a`short-cut in its flow, but instead is compelled to take a longer courseas above described and @thereby insure thel maximum heatexchangingeilect-,of the apparatus.

fIIi order to prevent-'the packing ystrips from Abecoming detached fromtheA baille when the latter is withdrawn'pfrom 'thel shell together withth'e' cluster 6r bundle'of .tubes 18 and 19, limiting mea-ns areprovided which in their preferred form consist of stop pins or screws 55which are securedtothe baille 44 and extend through transverse slots 56in the flanges of the respective packing'st rip,'the pinsI which passthrough the opposite flanges `orlegs -of the sameA stripbeinglpreferably staggered relatively to each other so. that the pins orscrews can be inserted in the baille from opposite sides of the'A .Samewithout`-interference with each other.

The ppposing ends of adjacent sections of the packing strip may either,abut Aagainst Ieach other as shown at 57l in Fig. 6 or they same mayextend one o .ver the other in the form of an overlapping or' telescopicjoint.'

as shown at 58 in Fig. 7, but in either case the opposing ends ofadjacent packing strip sections are arranged in `close .engagement soasjto form a practicallyjfluid-tight joint between the same'. l',Bymaking the'packing strips in sections `the same can'- be appliedtQ-the baille more readily and the same are also more ilexible inasmuchas the several'sections of each strip'` are free to adaptthemselves'individually -to the contour of the adjacent part of'tlleshell wall in-case any inaccuracies or irregularities Ioccur in thesame, and thereby provide a leaktight joint between the baille and thecylinder wall throughout the length of the opposing surfaces of thesemembers.

When the cluster of tubes is removed from the shell together with thebaille tube sheets and packing strips, the lateral movement of thepacking strips relative to the baille is limited by the stopping effectof the stop pins 55 engaging with the inner ends of the slots `56 in theflanges of the packing strips. Preparatory to introducing the tubes,sheets, baille and packing s'a-ips into the shell the packing strips arepressed inwardly toward the longitudinal edges of the baille aSullicient extent to permit the packing strips topass into the shell,and after these stripsI have been introduced into the shell the same'are released so as to permit the springs 54 to press the packing stripsoutwardly into engagement with the shell wall and form a' tight jointtherewith.

This means for packing the joint between thev baille and the 'shell Wallavoids the necessity of any accurate. or expensive fitting of the baillerelative to the wall of the shell vand instead permits of leaving aclearance space of varying width between the longitudinal edges of thebaille and the shell wall Vwhich permits of the free introduction of thebaille into the shell and the removal thereuse.

. v Moreover, thisy construction of packing device between the bailleand shell 1s very simple and mexpensive 1n construction and not ,onlycapable of being easily applied to the baille but is also not liable toder. f

I claim as my invention: d 1; A heat exchanger comprising a shell havinga fluid inlet and a fluid outlet, a

get out of or- -plurality of sets of tubes arranged in said shell, tubesheets mounted 'at opposite ends of said shell and connected withopposite ends of said tubes, a baille arranged between the sets of tubesand having longitudinal edges arranged adjacent to said shell, andpacking means interposed between the longitudinal edges of said bailleand said. shell and comprising a packing strip having a web engagingsaid shell and flanges on opposite longitudinal edges of said webwhichengage opposite sides of the longitudinal-edge portion of saidbaille, and spring means for holding said packing strip yieldingly inengagement with said shell. 2. A heat exchanger comprising a shellhaving a fluid inlet anda `fluid outlet,j a plurality of .sets of tubesarranged in said shell, tube sheets mounted at opposite ends 'of saidshell and Aconnected with opposite ends of said tubes, Va baillearranged between the sets oftubes and having longitudinal edges arrangedadjacent to said shell, and

packing 'means interposed between the longitudinal edges of said baileand said shell and comprising a packing strip having a web engaging saidshell and flanges on opposite longitudinal edges of said web whichengage opposite sides of the longitudinal edge portion of said baille,and a serpentine spring interposed between the edge of said baffle andthe inner side of said web and operating to hold the packing stripyieldingly in engagement with said shell.

3. A heat exchanger comprising a shell having a fluid inlet and a Huidoutlet, a plurality of sets of tubes arrangedin said shell, tube sheetsmounted at opposite ends of said shell and connected `with opposite endsof said tubes, a baille arranged between the sets of tubes and havinglongitudinal edges arranged adjacent to said shell, and packing meansinterposed between the longitudinal edges of said baille and said shelland comprising a packing `strip having a web engaging said shell andflanges on opposite longitudinal edges of said web which engage oppositesides of the longitudinal edge portion of said baille and are providedwith transverse guide slots, retaining pins secured to said baille andpassing through said slots, and spring means for holding said packingstrip yieldingly in engagement with said shell.

4. heat exchange comprising a shell having a fluid inlet and a fluidoutlet, a plurality of sets of tubes arranged in said shell, tube sheetsmounted at opposite ends of said shell and connected with opposite endsof said tubes, a baille arranged between the sets of tubes and havinglongitudinal edges arranged adjacent. to said shell, and packing meansinterposed betweenthe longitudinal edges of said baille and said shelland comprising a packing strip having a web engaging said shell andflanges on opposite longitudinal edges of said web which engage oppositesides of the longitudinal edge portion, said strip being made insections and the end of adjacent sections being close 'toathei l 5. Aheat exchanger comprising a shell having a fluid inlet and a fluidoutlet, a plurality of sets of tubes arranged in said shell, tube sheetsmounted at opposite ends of said shell and connected with opposite endsof said tubes, a baflle arranged between the -sets of tubes and havinglongitudinal edges arranged adjacent to said shell, and packing meansinterposed between the longitudinal edges of said baie and said shelland comprising a packing strip having a web sections and the ends ofadjacent sections abutting.

6. A heat exchanger comprising la shell having a fluid inlet and a iuidoutlet, a plurality of sets of tubes arranged in said shell tube sheetsmounted at opposite ends of said shell and connected with opposite endsof said tubes, a baille arranged between the sets of tubes and havinglongitudinal edges arranged adjacent to said shell, and packing meansinterposed between the longitudinal edges of said bale and said shelland comprising a packing strip having a web engaging said shell andflanges on opposite longitudinal edges of said web which engage oppositesides of the longitudinal edge portion of said baille, said strip beingmade in sections and the ends of adj acent sections overlapping one overthe other.

In testimony whereof I hereby afiix my signature.

HABLAN W. HOW.

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